diff options
author | David Young <dyoung@pobox.com> | 2020-08-25 15:23:01 (GMT) |
---|---|---|
committer | David Young <dyoung@pobox.com> | 2020-08-25 15:23:01 (GMT) |
commit | da4c72a138f0e418d3f72d6f095f5f40c92d9648 (patch) | |
tree | 90e9d04948cd29f179fb70914a435e4943e3d022 | |
parent | c492036b0d5a6dbcd2389af48fec95c80098210e (diff) | |
download | hdf5-da4c72a138f0e418d3f72d6f095f5f40c92d9648.zip hdf5-da4c72a138f0e418d3f72d6f095f5f40c92d9648.tar.gz hdf5-da4c72a138f0e418d3f72d6f095f5f40c92d9648.tar.bz2 |
Incorporate Mike's changes, fix some of my punctuation and markdown.
-rw-r--r-- | doc/SWMR Example.png | bin | 0 -> 81265 bytes | |||
-rw-r--r-- | doc/SWMRdataflow.png | bin | 0 -> 66196 bytes | |||
-rw-r--r-- | doc/vfd-swmr-user-guide.md | 50 |
3 files changed, 32 insertions, 18 deletions
diff --git a/doc/SWMR Example.png b/doc/SWMR Example.png Binary files differnew file mode 100644 index 0000000..e35624c --- /dev/null +++ b/doc/SWMR Example.png diff --git a/doc/SWMRdataflow.png b/doc/SWMRdataflow.png Binary files differnew file mode 100644 index 0000000..f28d86b --- /dev/null +++ b/doc/SWMRdataflow.png diff --git a/doc/vfd-swmr-user-guide.md b/doc/vfd-swmr-user-guide.md index e80ba98..894d523 100644 --- a/doc/vfd-swmr-user-guide.md +++ b/doc/vfd-swmr-user-guide.md @@ -1,26 +1,36 @@ # Welcome to VFD SWMR -Thank you for volunteering to test VFD SWMR. VFD SMWR is a new feature -of the HDF5 library that lets a process write data to an HDF5 file while -one or more processes read the file. Use cases range from monitoring -data collection and/or steering experiments in progress to financial -applications. +Thank you for volunteering to test VFD SWMR. + +SWMR, which stands for Single Writer/Multiple Reader, is a feature +of the HDF5 library that lets a process write data to an HDF5 file +while one or more processes read the file. Use cases range from +monitoring data collection and/or steering experiments in progress +to financial applications. + +The following diagram illustrates how SWMR works. + +<img src = SWMRdataflow.png width=400 /> + VFD SWMR is designed to be a more flexible, more modular, -better-performing replacement for the existing SWMR feature. VFD -SWMR allows HDF5 objects (groups, datasets, attributes) to be -created and destroyed in the course of a reader-writer session. It -compartmentalizes much of the SWMR functionality in a virtual-file -driver (VFD), thus easing The HDF Group's software-maintenance burden. -And it makes guarantees for the maximum time from write to availability -of data for read, provided that the reading and writing systems and -their interconnections can keep up with the data flow. +better-performing replacement for the existing SWMR feature. + +* VFD SWMR allows HDF5 objects (groups, datasets, attributes) to be + created and destroyed in the course of a reader-writer session. +* It compartmentalizes much of the SWMR functionality in a virtual-file + driver (VFD), thus easing The HDF Group's software-maintenance burden. +* And it makes guarantees for the maximum time from write to availability + of data for read, provided that the reading and writing systems and + their interconnections can keep up with the data flow. + +For details on how VFD SWMR is implemented, see [LINK to RFC]. # Quick start -Follow these instructions to download, configure, and build the VFD SWMR -project in a jiffy. Then install the HDF5 library and utilites built -by the VFD SWMR project. +Follow these instructions to download, configure, and build the +VFD SWMR project in a jiffy. Then install the HDF5 library and +utilites built by the VFD SWMR project. ## Download @@ -101,15 +111,19 @@ To run a bigset test, I open a couple of terminal windows, one for the reader and one for the writer. I change to the `test` directory under my build directory, and I run the writer in one window: +``` % ./vfd_swmr_bigset_writer -n 50 -d 2 +``` and in the other window, I run the reader: +``` % ./vfd_swmr_bigset_reader -n 50 -d 2 -W +``` The writer will wait for a signal before it quits. You may tap Control-C to make it quit. If you don't want it to wait, then you can -pass option flag -W. (The reader accepts the same flag.) Use the `-q` +pass option flag `-W`. (The reader accepts the same flag.) Use the `-q` option to suppress the progress messages that the programs write to the standard error stream. @@ -119,7 +133,7 @@ dataset with content in three source datasets in the same HDF5 file. The `-M` option works like `-V`, only the writer creates the virtual -dataset on three source datasets each in a different HDF5 file. +dataset on three source datasets, each in a different HDF5 file. ## The VFD SWMR demos |